406903

MIR10B

epithelial-mesenchymal transition (EMT) is a key process in the tumor metastatic cascade that is characterized by the loss of cell-cell junctions and cell polarity, resulting in the acquisition of migratory and invasive properties. Recent evidence showed that altered microRNA-10b (miR-10b) expression was implicated in the occurrence of EMT of breast cancer. However, the exact role and underlying mechanisms of miR-10b in the EMT of breast cancer still remain unknown. In this study, miR-10b was found to be upregulated in breast cancer tissues and breast cancer cell lines and the expression of miR-10b was shown to be closely correlated with aggressiveness in breast cancer. Treating breast cancer cells with the miR-10b inhibitor increased E-cadherin expression while decreasing vimentin expression. At the same time, on inhibition of miR-10b, the invasion and proliferation ability of breast cancer cells also decreased. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that induces EMT in multiple cell types. Here, we identified miR-10b as a target gene of TGF-beta1. The expression of miR-10b increased during TGF-beta1-induced EMT of breast cancer cells. Further study showed that inhibition of miR-10b expression partially reversed the EMT, invasion and proliferation induced by TGF-beta1 in breast cancer cells. Taken together, these results demonstrated a novel function for miR-10b in TGF-beta1-induced EMT in breast cancer and increased their metastatic potential. MiR-10b might become a possible target for gene therapy in breast cancer.

Laryngeal carcinoma is the second most common malignancy of the head and neck squamous cell carcinoma. Therefore, there is an urgent need to understand the molecular mechanism of its metastasis. The present study was designed to investigate effects of miR-10b on the invasion and migration of laryngeal Hep-2 cells. We found that miR-10b had limited effects on cell proliferation; however, it can significantly promote the migration and invasion of Hep-2 cells. Further studies revealed that overexpression of miR-10b can induce the epithelial-mesenchymal transition (EMT) of Hep-2 cells by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin (N-Cad) with a concomitant decrease of E-cadherin (E-Cad). However, the messenger RNA (mRNA) and protein level of transcription factors such as Snail, Slug, Twist and ZEB was not changed during this process. Bioinformatic analysis revealed that miR-10b can directly target CDH1 (E-Cad gene) at nucleotides 461 and 481 within the 3'-UTR. This was confirmed by the results that miR-10 downregulated the protein and mRNA levels of E-Cad via a time-dependent manner and luciferase analysis by use of four-nucleotide substitution in the core binding sites. The present study provided a better understanding of laryngeal carcinoma metastasis and the roles of miR-10b during this process.

Although it is well known that exaggerated proliferation, metastasis and the mesenchymal subtype is related with worst prognoses in glioblastoma (GBM) and that transforming growth factor-beta1 (TGF-beta1) is a potent factor in regulating the proliferation, migration and epithelial-mesenchymal transition (EMT) phenotype of GBM, the detailed mechanisms are still far from elucidated. MicroRNAs (miRNAs) are small non-coding RNAs which play critical roles in various diseases by regulating target gene expression. We report that miR-10b, a molecule downstream of TGF-beta1, is involved in TGF-beta1-regulated GBM cell proliferation, migration and EMT. We found that exposure of GBM cells to TGF-beta1 significantly upregulated miR-10b expression. Overexpression of miR-10b promotes GBM cell proliferation, migration and EMT, whereas depletion of miR-10b obtained reverse effects. Further studies uncovered that some tumor-associated genes including epithelial cadherin (E-cadherin), apoptotic protease activating factor 1 (Apaf-1) and phosphatase and tensin homolog (PTEN) are target genes of miR-10b. In human GBM xenografts, antagomiR directed against miR-10b markedly suppressed tumor growth, and the tumor volume shrunk from 1252.5+/-285 to 873.4+/-205 mm3 after antagomiR10b treatment for 3 weeks compared with the control group (P<0.01). Taken together, our data collectively demonstrate that the proliferation, migration and EMT features of GBM cells can be regulated by TGF-beta1 stimulation through controlling miR-10b. Thus, our findings provide a rationale for targeting TGF-beta1 or miR-10b for the treatment of GBM.

BACKGROUND: Cell adhesion molecules (CADMs) comprise of a protein family whose functions include maintenance of cell polarity and tumor suppression. Hypo-expression of CADM2 gene expression has been observed in several cancers including hepatocellular carcinoma (HCC). However, the role and mechanisms of CADM2 in HCC remain unclear. METHODS: The expression of CADM2 and miRNA-10b (miR-10b) in HCC tissues and cell lines were detected using real-time PCR and Western blotting. Immunofluorescence was used to detect epithelial-mesenchymal transition (EMT) progression in HCC cell lines. Dual-luciferase reporter assay was used to determine miR-10b binding to CADM2 3'UTR. Wound healing assay and Transwell assay were performed to examine the migration and invasion of HCC cells. RESULTS: We report the effect of CADM2 as a tumor suppressor in HCC. Firstly, we confirmed that CADM2 expression was significantly down regulated in HCC tissues compared to normal tissues according to TCGA data analysis and fresh HCC sample detection. Secondly, overexpression of CADM2 could inhibit EMT process, migratory and invasion ability of HCC cells. Furthermore, the results indicated that CADM2 is a direct target of miR-10b in HCC cells and miR-10b/CADM2 modulates EMT process and migration ability via focal adhesion kinase (FAK) /AKT signaling pathway in HCC. CONCLUSIONS: Our study demonstrates that miR-10b-CADM2-FAK/AKT axis plays an important role in HCC metastasis, which might be a novel potential therapeutic option for HCC treatment.